One more manupulation is wash trading.
This is making fake volumes for some coins. Bot trading in circle "buy sell buy sell"
In regulated exchanges its restrickted.
Wash trading is the way exchanges scam users. Last week there was report about exchanges using wash trading and create fake volume.
According to the report there were two well known exchanges, Okex and Huboi.
More than 60% of volume at Huobi and more than 90% of volume at Okex reported as fake volume.
Okex CEO claimed that they can prove at least 10% of their volume is real at twitter.
All exchanges must be regulated and must be easily reachable buy users.